Train-control system



W. W. MACFABLANB TRAIN CONTROL SYSTEM. APPIJICATION FILED NOV, 29, 1920.

1 A3 1 747. Patented (M. m, 1922 2 SHEE,TSSHEET l.

Pat-exited 001.1%1922 Z SHEETSSHEE1 2.

mama-a WILLIAM W. MACFARLANE, OE ELKINS PARK, PENNSYLVANIA, ASSIGNOR TO MAC- ZFARLANE COMMUNICATIONS CORPORATION, OF NEW YORILN. Y., A CORPORATION OF DELAWARE.

TRAIN-CONTROL SYSTEM.

Application filed November 29, 1920. SeriaLNo. 426,919.

To all whom it may con-cm:

Bev it known that 1, WILLIAM W. Mac A FARLANE, a citizen of the United States, and

a resident of Elkins Park, county of Montgomery, and State of Pennsylvania, have inventedcertain new and useful Improvementsin Train-Control Systems, of which the following is a specification.

, The present invention relates generally to systems of train control and is more particularly an improvement on the inventions disclosed in applications Serial Number 203,378, filed November 22, 1917, now Patent No. 1,389,258, and Serial Number 372,--

440, filed April 9, 1920.

The main object of this invention is to dispense with the necessity of having a constant current flow in the trafiic rails and also has for an object reducing the number of wires that are necessary in transmitting messages between a wayside station and a moving train or between two trains or between different ends of the same train.

' 'In the application Serial No. 372,440, filed April 9, 1920, I disclosed means whereby a normally incomplete circuit is provided,

' which circuit is made complete by the train bridging the traflic rails; and also a local normally completecircuit. In the construction there shown, however, there was employed, in addition to the two line wires,

' a third line wire, and one of the main feacation proceeds.

-tures of this invention is the elmination of this third line wire and the consequent cost thereof.

. Other features will appear as the specifi- In the accompanying drawings the invention is disclose-d in several concrete and preferred forms in which Figure 1 is a diagrammatic view of the system showing one form of the invention.

' Figure 2 is a diagrammatic view of a modified form of car-carried circuit.

1 and 2 indicate line wires paralleling the traffic rails 4 and 5. Wayside stations or central oflices 6 are connected with line wires 1 and 2 at suitable intervals, say of one hundred miles. One rail 5 of the trafiic track is divided by suitable insulation '4' intoblocks or sections of suitable length depending upon the local traflic conditions and other circumstances, as will be understood. 8 and 9 indicate two wires connected with line wires 1 and 2 and with rails 4 and 5.

said shunt being normally ruptured by armature 11 under the control of magnet 12, said magnet 12 constituting the core of a transformer winding 13 in inductive relationto winding 14 of wire 8. Conductor 8 is a part of a local and normally complete circuit consisting of said conductor rail 4, conductor l5 and line wire 2. Conductors 8 and 9 constitute two branch wires connected to opposite rails, but not bridging them, and also connected to line wires 1 and 2, and wire 15 is a third branch wire that extendsbe tween rail 4 and line wire 2, which is the same rail and the same line wire with which branch wire 8 is connected.

17 indicates the car having a winding 18 in circuit with rail 4 and in inductive relation to telephone circuit 19 having battery 20 and provided with the usual sending and receiving devices as shown. As disclosed in said Patent No. 1,389,258 said winding 18 has an extremely low resistance.

The wayside station has a local circuit that may be traced as follows: from battery 21 by way of transmitter 22, conductor 23, key 24 (when depressed), conductor 25, transformer Winding 26 and conductor 27, back to battery 21. The fluctuating speech current set up in transformer winding 26 induces a similar current in transformer winding 28, that flows by way of conductors 29 and 30, key .31 and conductor 32 to the line wires. From the line wires the current flows by Way of branch wire 9 and -winding 13 to rail 5, thence across the car erated 1n the car' will be transmitted to the shunt 10 is connected'between 8 and 9,

line wires and coil 28 over the circuits previously described, and button 24, now being elevated, current will pass from coil 26 to receiver 33 as followszfrom coil 26 by wire34, including receiver 33, to button 24, and thence by conductor 25 back to coil 26. The foregoing description of the circuits assumes thatthe train is travelling from right to left and is in advance of conductor 15 and behind conductor 8, but it will be evident that if the trainis in advance of cond uctor 8 and behind conductor 15, then current flows toor from winding 18 oii'the train between the conductor, 8 inrear of train andthe conductor in front of the train.

In case the attendants of two trains wish to speak with each other, the current will pass from .thetrain in one block over the local circuits, .as previously described,

to the line wires, and thence to thelocal circuits of the block occupied by the other train. This circuit will be as follows: from coil 18 of car at right hand side of Fig, 1, to raill4, thence by conductor 15 to line wire 2, conductor 8, rail 4 and back to winding 18. This induces acurrent 'in coil 13 17, rail 4, conductor 15, 1inewire 2, conduc tor 15 at left hand side of Fig. 1, rail 4, car 17, conductor 9, linewire 1, 'conductor'9 at right hand side Fig. 1, back to coil- 13. This. in turn induces a current in coil '14 at left hand side of Fig. 1, which passes by way of conductor 8 to rail 4, coil 18 conductor 15 line wire 2, conductor 8 and back to coil '14. The same thing will occur when attendants at opposite ends of a train occupying more than one block, wish to speak with each other, but if the train is. entirely within the same block, the. current may flow along the rail from one winding-18 to another without going'over the line wires, and the circuit would then be as follows: from winding 18 of onecar along rail 4 to windin'g 18 01 1 another car, across carto rail 5, along ra1l 5 to first car, across the first car to rail 4.

or both, along theline of way, to indicate to the attendant of atrain that the. train -dispatcher desires to communicate with him,

.means are employed for energizing coil12 or ringinga'bell, or the like. his is ac-- 'coniplished. by depressing key 31, thereby follows: from battery 21 to key 31, conduc- 9 and coil 13, rail 5, car 17, rail -4, conductor 8 and coil 14 to line wire 2, and by wire 37 back tobaiztery 21. In describing the local wayside station, mention has been made of key 24, which is depressed and raised inamanner well under stood to cut in'and out the receiving and transmitting circuits, and it will be understood that in accordance with well-known practice and asdescribed in the applications -6 6 previously referred to, 'such device might which passes over conductor 9, rail 5, car

sufiiciently to attract armature 11, thereby clo'sing shuntlO and illuminatin light 35,

placing a powerful source -of current, here .shown as battery 21, in circuit. with line wires 1 and 2' and'establishing a circuit as j' tor 30, to line wire 1,'by way of conductor 'erator to hear and speak at the same time,

recourse may, be hadto the construction shown in Figure2 which is-intended'to be used in the system previously described. As

shown in'thisl. figure, the car-carried circuit? 5 consists of separate transmitting and receiving circuits 40 and 41, and in these circuits are included what may be called secondary windings 42 and 43.- What may b'e called primary windings 44 and '45-"are connected in parallel as shown andare both connected .with the body of the car and thereby-to the rail, as will be understood, ,Preferably, number 46 is acopper bar'or cable of verylow resistance. p 1

An illustration of the relative'resistances otthe wiring showuinIFig' 2 is as follows: The copper bar 46 has a value which may be designated as'one" million circular mills. This, however,-doesn0t include the 9 0. winding44 which-:may' consist of seventy turns of No.2 double cotton covered wire. Winding 43 may consist of three thousand turnsof No; 29-wire: Winding 45"may be three hundred seventy-two turns of No. 22

wire and thewire by means of which this winding connected to the copper bar may be No. 16 wire.- Windin 42 may be eighteen hundred -tu1nsof o. 20 wire. The

may. be considered asbeing eight hundred rails- It will now be understood that the through copper cable 46 and winding 44 willpreferthis path to that including the winding 45 which latter is of a very much higher resistance than 44and 46 and that in impressin current from the circuit con taining winding 42 the bulk of it will naturally'pa through the rail's'because their resistance is lower than that of the path produced by 44 and 46, but suifioient current is shunted through'44 and 46 to operate the recelver.

.Iclaim':

A sy tem of the character described comprisin two line wires, traffic rails, two

branch wires connected to the line wires and connected to, but not bridging, the rails, a

third branch wire extending between one of the line wires and one of the rails and forming. with one of the two first branch wires with one of the line wires and with one of the rails a normally incomplete circuit, said .third branch forming'with the other of said two first branch wires with one of the line wlres and with one of the rails anormally complete local circuit, an inductive resistance value of. each rail of the track 100 current that'will be .diverted from the rail .105 To give a signal, either.aud1ble .or visual:

coupling between the two first branch wires, a car for completing the normally incomplete circuit by bridging the rails, means on the car responsive to current in the local circuit and for impressing currentlon said local circuit, and a Wayside station responsive to current impressed by the local circuit upon the line Wires, and for impressing .current on the line Wires to energize the local circuit.

- Signed at Elkins Park, in the county of =Montgomery and State of Pennsylvania, this 15th day of Nov., 1920.

WILLIAM W. MACFARLANE. 

